The DA \(\phi _{\pi \sigma }\)  is not needed by us in this work explicitly. Thus, we refrain from quoting it here.
It can be found in [1]}.
If \(\phi _{3\pi }=0\)  Eq. (REF ) reduces to the well-known WW approximation of the DAs
\(\phi _{\pi p}^{WW}\,=\, 1\,, \qquad \phi _{\pi \sigma }^{WW}\,=\,6\tau \bar{\tau }\,.\) 
